My favorite Ren Faire story:

I knew a guy who kept a Starfleet insignia pinned to the inside of his garb. A few times per season, some folks would come to the Faire cosplaying as a Star Trek landing party, investigating a “primitive” world.

He would take them aside, show his insignia, and identify himself as a Starfleet officer on a cultural research mission. He’d call them out for breaking the Prime Directive and ruining his research. Then he’d demand to know what ship they’re from, and threaten to get them court martialed if they didn’t change into something less conspicuous.